Geomatic Approach Research Articles

Land changes detection on Rote Island using harmonic modelling method

Rote Island is one of the islands in East Nusa Tenggara. In this island, land changes occur significantly. This land changes can be detected by Landsat images. These images are obtained from the big data engine. The big data engine used is the Google Earth Engine. This study aimed to detect land changes with harmonic modelling using multitemporal Landsat images from the big data engine. Harmonic modelling is used in monitoring changes in Normalized Difference Vegetation Index values in a multitemporal manner from Landsat images. Processing is done using the Geomatics approach. Land changes on Rote Island generally occur on coastal and savanna. Land changes on land generally have vertical deformation on its movement and horizontal on the savanna. The land changes accuracy result is 95% in 1,96σ. This method can be used for rapid mapping of land changes monitoring.

Mapping the water erosion risk in the Lakhdar river basin (central High Atlas, Morocco)

ABSTRACTThe objective of this study is to develop a methodology using the remote sensing and Geographic Information System to map soil degradation by water erosion and highlighting the various levels of soil degradation in the Lakhdar river basin (central High Atlas) during the period between 1987 and 2014. This allows producing a map of soil degradation risk, which can be used as reference document for the decision-makers. The methodology develops a geomatics approach based on the processing of satellite images, using the analysis and the interpretation of spectral indices, such as the Form Index, the Coloration Index, the Brightness Index, and the Normalized Difference Vegetation Index (NDVI). The results show that the surface of soil strongly degraded decreased about 900 ha during the period of study whereas the surface of soil weakly and moderately degraded was subject of a progressive increase for an approximate total of 2800 ha over 27 years. Moreover, the method of spectral indices allowed us to assess and locate soil quantitative loss (organic matter, mineral salts, texture, fertility, etc.) due to the water erosion and climate change. These results are decisive when it comes to establish priority zonation for the interventions of erosion control.

Climate Change and Impact of Projected Sea Level Rise along Cauvery Delta, Tamil Nadu, India - A Geomatics Approach

The phenomenon of global warming is expected to cause chains of environmental issues in the planet earth especially the maritime states of the world foresee substantial adverse effect due to the sea level rise. Hence, the scientists from all over the world have embarked into number of studies to visualize the impact of sea level rise and to make possible remedial and protective strategies for the resources at risk. In this connection, the present study is an attempt to visualize the zones of possible inundation due to accelerated sea level rise and the related impacts. The study has used various elements of emerging geospatial technology like Remote Sensing, GIS, photogrammetry, etc. and also brought out information on how precise impact analysis can be done due to IPCC AR5 2013 (Inter Governmental Panel for Climate Change) projected accelerated sea level rise of 42 cm (minimum) to 98 cm (maximum) from present day mean sea level (MSL) in next 100 years. Keywords Sea level rise; Cauvery Delta; Remote Sensing; GIS; GPS; Tamil Nadu coast DOI: https://doi.org/10.23953/cloud.ijarsg.364

Application of a Geomatics Approach for the Diachronic Study of the Meditterannean Coastline Case of Tangier Bay

The coastline is one of the country’s most important environmental and economic resources. However, it is a delicate and highly coveted environ-ment on which many factors of evolution interact, both anthropogenic and natural. This work is concerned with the diachronic study of the coastline of the Mediterranean coast, particularly the coastal fringe at the level of Tangier Bay. In order to experimentally confirm the numerical models used and to take part in the development of an accurate, reliable and rapid decision support system for the assessment and remediation of the risks of accretion and coastal erosion, the methodology followed consists of the application of automatic analytical techniques, based on a geomatics approach, using a multi-temporal photo-interpretation, a Geographical Information System (GIS) and a computerized data analysis system (DSAS: Digital Shoreline Analysis System). The change rate will be calculated from the multi-date maps (1981-96 and 2017) using the End Point Rate (EPR). To achieve our objective, the study area was divided into three sectors from East to West: El Ghandouri Beach, Malabata Beach and the municipal square adjacent to the port. The GIS analysis of the data obtained shows that the coastline is present by location and for the three periods of comparison of the remarkable zones of erosion and sedimentation.

Geo-Ecological Change of Border Areas Between Khasi Hills and Southern Plains of Assam, A Case Study with Geomatics Approach

Geo-Ecological Change of Border Areas Between Khasi Hills and Southern Plains of Assam, A Case Study with Geomatics Approach

Integrating geomatic approaches, Operational Modal Analysis, advanced numerical and updating methods to evaluate the current safety conditions of the historical Bôco Bridge

This paper proposes a multidisciplinary approach, combining the terrestrial laser scanner, ambient vibration tests and minor destructive tests, to characterize an early reinforced concrete bridge in Portugal: the Bôco Bridge. All methods are complemented by advanced numerical simulations and a coarse to fine calibration strategy, based on the Douglas-Reid and the non-linear least squares approaches. Results obtained corroborate the robustness of the proposed approach, with an average relative error in frequencies of 1.2% and an average modal assurance criterion of 0.91. Considering this model, its current safety conditions were evaluated, obtaining a minimum safety factor of 2.1.

An integrated geomatics approach to groundwater potential delineation in the Akoko-Edo Area, Nigeria

A groundwater prospect map was developed for the Akoko-Edo Local Government Area in Edo State in Nigeria using topographic, geological and soil maps for the area and remote sensing imagery. LandSat-OLI image were subjected to haze reduction and preprocessing algorithms, respectively. Reclassified raster layers of lineaments density, lithology, slope steepness, drainage density, geomorphology, topographic wetness index, land use/land cover and soil were generated from the acquired datasets. All these themes and their individual features were then assigned weights according to their relative importance in groundwater occurrence and the corresponding normalized weights were obtained based on the Saaty’s Analytical Hierarchical Process. These parameters were then combined using weighted overlay tool in ArcGIS 10.3 to produce groundwater potential map of the study area. The results showed that 0.02% of the area is likely to have poor prospects of finding a suitable groundwater resource, 24% of the area is likely to have fair prospects, 64% of the area is likely to have moderate prospects and 12% of the area is likely to have good prospects. The study concludes that geomatics application can play an important role with geophysical survey in groundwater exploration.

Application of UAV photogrammetry for the multi-temporal estimation of surface extent and volumetric excavation in the Sa Pigada Bianca open-pit mine, Sardinia, Italy

In open-pit mines, monitoring of topographic and volumetric changes through time is found to be of great importance to support excavation stages and to plan rehabilitation strategies. In this work, we describe a geomatic approach to assess changes in surface mine extent and to quantify excavated volume in the Sa Pigada open-pit mine, Sardinia, Italy. We performed two drone-based photogrammetric surveys in 2013 and 2015, and by means of the Structure from Motion (SfM) technique, we obtained related 3D dense point clouds and digital orthophotos. Images were georeferenced thanks to a series of ground control points surveyed with geodetic GPS. Distances between the two clouds were estimated with the recent Multiscale Model to Model Cloud Comparison (M3C2) plug-in included in the CloudCompare open-source software. Starting from cloud-to-cloud distances, we calculated the excavated volume of mineral resources between the two surveys. Results of the M3C2 comparison supported the analysis of the two orthophotos, through which accurate limits of the 2013 and 2015 active mine areas, rehabilitated area and temporary dumps were identified and drawn in a digital map. Results obtained in this study suggest that the applied geomatic techniques are suitable for performing accurate change detection analysis in open-pit environments and represent a valid support for scientists and technicians allowing to monitor with high spatial and temporal resolutions. This approach can be also considered a valid tool to reduce environmental impact from mining.

Geomatics approach to surveys for Late Antiquity buildings. The Episcopal Palace in Side, Turkey

Side is one of the best preserved cities of Antiquity in the historical Pamphylia area of Anatolia, current Antalya, Turkey. This archaeological site shows numerous standing structures and monuments spanning from the 7th century BC to the 12th century AD. The aerial and terrestrial survey conducted in 2016 was centred on the so called Episcopal Palace and the Fountain area with a total surveyed surface of 5,900 mq. The aim of the work was to analyse and recreate the existing structures in a 3D environment to help in later research questions like architectural features, building construction design and upgrades or location of the palace within the urban area. This paper intends to highlight the value of an accurate ground control point network to record an ancient urban site and its advantages when using CAD and GIS software. Moreover, it will also focus on the methodology used to capture the data used on the area of the Episcopal Palace to create an accurate 3D reconstruction of the remaining structures (with Structure from Motion) for further analysis and interpretations; merge classic survey methods (Total Station and Global Positioning Systems) with relatively new methodologies and hardware (Unmanned Aerial Vehicle); check and test the accuracy and the derived errors (data surveying gaps, traversing adjustments, coordinate and projection systems) that arise during post-processing (ellipsoid/geoid highs differences, noise reduction, fusion between datasets). Possible uses of the created/resulting data from the georeferenced point clouds, the model as a visual tool (orthophotos and 3D Mesh) for classic planning (elevations and sections) and its utility in a GIS environment (ArcScene) are also discussed. At the end of the paper report, some questions about the utility of the 3D reconstructions and models in Heritage as well as their utility for the archaeological record will be discussed.

Present and future of desertification in Spain: Implementation of a surveillance system to prevent land degradation

Mitigation strategies are crucial for desertification given that once degradation starts, other solutions are extremely expensive or unworkable. Prevention is key to handle this problem and solutions should be based on spotting and deactivating the stressors of the system. Following this topic, the Spanish Plan of Action to Combat Desertification (SPACD) created the basis for implementing two innovative approaches to evaluate the threat of land degradation in the country.This paper presents tools for preventing desertification in the form of a geomatic approach to enable the periodic assessments of the status and trends of land condition. Also System Dynamics modelling has been used to integrate bio-physical and socio-economic aspects of desertification to explain and analyse degradation in the main hot spots detected in Spain.The 2dRUE procedure was implemented to map the land-condition status by comparing potential land productivity according to water availability, the limiting factor in arid lands, with plant-biomass data. This assessment showed that 20% of the territory is degraded and an additional 1% is actively degrading. System Dynamics modelling was applied to study the five desertification landscapes identified by the SPACD. The risk analysis, implemented on these models, concluded that ‘Herbaceous crops affected by soil erosion’ is the landscape most at risk, while the Plackett-Burman sensitivity analysis used to rank the factors highlighted the supremacy of climatic factors above socioeconomic drivers.

From monument to geosite: a geomatic approach to link geological and cultural heritage

This short note aims to raise the awareness in geological heritage and geoconservation focusing on the links between geomatic and historical/archaeological heritage.The main goal of this research is to identify an approach that shows how Geological and Cultural Heritage are so strictly linked one to each other to be considered different pieces of the World's evolution puzzle. Geological heritage has an important role for understanding the World heritage, representing a tangible asset of human and natural developments. Starting from minero-petrographic analysis of building materials of historical and archaeological assets in Italy, it is possible to carry out a study about their mining area, tools and extraction, quarrying methods and transportation. The results of this approach represent a preliminary step toward the integration of geology and archeology into an holistic analysis. Moreover they have valuable potential for protection and conservation, education and sustainable development, in accordance with the UNESCO guidelines and criteria for establishing National Geoparks.

Landslide Cartography at the Region of Nabeul-Hammamet Based on Geographic Information System and Geomatic

Landslides are one of the most significant natural damaging disasters in hilly environment [1]. The location of our study area is to the north of Tunisia, home to several manifestations of land instabilities, we bring to study this area of interest by GIS and geomatic approach to reduce social economic losses due to landslides. The performance of a cartographic data base for the landslide study in the Cap-Bon region was realized through studying geologic 1/50,000 and topographic 1/25,000 maps, aster optic Remote Sensing, land observation, and climatologic seismic data. These data will be digitalized, georeferenced, vectorized, spatially analyzed, classified and geotreated in order to produce a landslides card. The findings have shown that fields with smooth and friable lithology which are located at rather important seismic zones (more than 4 at Richter’s scale) have some stability. However, the most endangered zones are in the North-West around Oued El Kbir and El Ain. Realizing this work helps to determine the most hazardous zones so that policy makers have an effective field intervention.

Estimating Horizontal Displacement between DEMs by Means of Particle Image Velocimetry Techniques

To date, digital terrain model (DTM) accuracy has been studied almost exclusively by computing its height variable. However, the largely ignored horizontal component bears a great influence on the positional accuracy of certain linear features, e.g., in hydrological features. In an effort to fill this gap, we propose a means of measurement different from the geomatic approach, involving fluid mechanics (water and air flows) or aerodynamics. The particle image velocimetry (PIV) algorithm is proposed as an estimator of horizontal differences between digital elevation models (DEM) in grid format. After applying a scale factor to the displacement estimated by the PIV algorithm, the mean error predicted is around one-seventh of the cell size of the DEM with the greatest spatial resolution, and around one-nineteenth of the cell size of the DEM with the least spatial resolution. Our methodology allows all kinds of DTMs to be compared once they are transformed into DEM format, while also allowing comparison of data from diverse capture methods, i.e., LiDAR versus photogrammetric data sources.

Assessment of pollution level in a Himalayan Lake, Kashmir, using geomatics approach

Pollution indices aggregate concentrations of several water quality parameters into a single quantity to indicate the general status of pollution in a region. In this study, a variant of the previous water quality index was used to evaluate the pollution status in the Wular Lake, Kashmir, which is a Ramsar site and wetland of international importance. The index termed as water quality status index (WQSI) is considered as a simple pollution indicator to support management actions in the Wular Lake, Kashmir. WQSI is a valuable and unique rating to depict the overall water quality status and pollution level of the waterbody in a spatial context and is also capable of dealing with those water quality parameters which do not have well-developed standard values. In this study, the water quality of the Wular Lake was investigated in June 2013 for 21 sample locations. The index used in this work is composed of 13 measurable physico-chemical parameters – pH, dissolved oxygen, chemical oxygen demand, biological oxygen demand, alkalinity, hardness, chloride, total dissolved solids, ammonia, iron, nitrite, nitrate and fluoride. The generation of WQSI is based on weighted overlay technique, in which interpolated raster maps were generated for all the 13 water quality parameters and weights are assigned to each and every parameter using analytic hierarchy process technique, considering their status as benefit or cost criteria. Based on the value of WQSI, the whole lake was divided into five zones, comprising least polluted zone (23%), moderately polluted zone (20%), high polluted zone (30%), very high polluted zone (22%) and extremely polluted zone (5%). From this study, it has been found that 60 km2 (77%) of total lake area constitutes the moderate to extremely polluted zone and only 18 km2 (23%) of the total lake area constitutes the least polluted zone, which is in the north-west region of the lake. The study reveals that the world-famous Wular Lake is undergoing the eutrophication process and as a result of which the lake is losing its water holding capacity to deal with the disastrous flood problem in Kashmir region.

A geomatic approach for emergency mapping of shallow landslides

Nel presente contributo viene proposto un approccio geomatico per mappare e caratterizzare dal punto di vista geomorfologico i fenomeni franosi superficiali in situazioni di emergenza. Il metodo e stato applicato durante il rilevamento di una frana che il 27/10/2013 ha interessato la falesia costiera della localita Baia dei Porci, nel Comune di Monte di Procida, in provincia di Napoli. Durante il rilevamento, eseguito parzialmente da barca, sono state scattate 95 foto successivamente elaborate con il software Agisoft PhotoScanTM. Il prodotto ottenuto dall'elaborazione e stato un modello digitale 3D della frana (DEM), georeferenziato nel sistema UTM 33N-WGS84. Dall'elaborazione del DEM eseguita in ESRI ArcGisTM e stato possibile ottenere la carta topografica della frana in scala 1:500, la carta delle pendenze, l'area delle zone di distacco e di deposito ed il volume del materiale franato.Visti i risultati ottenuti si ritiene che l'approccio proposto sia idoneo per essere applicato in situazioni di emergenza provocate da frane superficiali, a supporto delle autorita di Protezione Civile.

An archival geomatics approach in the study of a landslide

Geomatic approaches were used to investigate a landslide in the Emilian Apennines in northern Italy which occurred during excavation works for high-speed railway tunnels between 2002 and 2007. The landslide damaged three buildings located on the upper part of a hillside. At the site of interest, the high-speed railway system included three contiguous tunnels—the main tunnel and two connecting tunnels, “odd” and “even”—all crossing the “Chaotic Complex” formation. The archival multi-temporal digital photogrammetry technique was employed for photogrammetric surveys performed in 1998, 2004 and 2007, at a mean scale of about 1:8000. For all the surveys, stereo pairs of the area were available, and the black and white photo-frames were scanned using a Wehrli Raster Master RM2 photogrammetric scanner (12-μm resolution). Digital images were obtained, with a ground resolution in the range of 9–10 cm. The reference coordinates of the Ground Control Points (GCPs), as required for the external orientation of the images, were measured in 2009 in a stable area using GPS methodology. Orientation of the images was carried out with SOCET SET software, obtaining orientation residuals in the order of a few centimetres. An approach based on the multi-temporal sets of photographs was used, comparing the coordinates and amplitudes of the motion vectors. In doing so, 3D vectorial representations were obtained, providing displacements of about 14 cm in the initial period (1998–2004) and of about 25 cm in the latter period (2004–2007). From a chronological point of view, this data corresponded with both the beginning of the damage and the progression of the excavation of the tunnels, thus confirming the vulnerability of the Chaotic Complex to stress changes during the works.

An Indicator Model of the Spatial Quantification and Pattern Analysis of Urban Sustainability: A Case Study of Cincinnati, Ohio

Shen & Guo (2014) have recently developed an array of urban sustainability indicators (USIs) as a tool to measure urban sustainability. Using 2006 data for Saskatoon, Saskatchewan, Canada, they developed a theoretical integrated USI model with a hierarchical index system, to spatially monitor urban sustainability using geo-matic approaches and further statistically detect its spatial patterns. The purpose of this study is to apply Shen and Guo’s general approach to a major American city, Cincinnati, Ohio, utilizing U.S. census data from 2010, to test its utility beyond the original Canadian test case. In doing so, the model and its indicator structure were modified for the American context after a further review of sustainability indicators. Unlike Shen and Guo, however, the model is not subjectively weighted. Nevertheless, the revised model similarly applied both statistical analysis and geo-statistical analysis to explore how urban sustainability was spatially distributed and what spatial patterns (random, dispersed or clustered) for the indices could be found among Cincinnati’s census tracts. This work confirms Shen and Guo’s conclusion that geo-matic tools can be applied to detect spatially urban sustainability patterns, which can be provided visually for urban planners, managers and administrators for use in future policy making and implementation.

The role of spatial data and geomatic approaches in treeline mapping: a review of methods and limitations

In the debate over global warming, treeline position is considered an important ecological indicator of climate change. Currently, analysis of upward treeline shift is often based on various spatial data processed by geomatic techniques. In this work, considering a selection of 31 reference papers, we assessed how the scientific community is using different methods to map treeline position and/or shifts using spatial datasets. We found that a significant number of published studies suffer from a low degree of awareness of processed data, which outcomes in potentially unreliable results that may compromise the validity of inference from the studies. Moreover, we propose an operational approach for easily incorporating consideration of spatial data quality, so as to improve reliability of results and better support ecological conclusions. Finally, we present a simulation of potential treeline vertical error for the Alpine region of Northern Italy, as driven by primary data quality.

Use of Geomatic Approaches to Characterize Arqa River Basin: A Typical Coastal Lebanese River

Use of Geomatic Approaches to Characterize Arqa River Basin: A Typical Coastal Lebanese River

Use of Geomatic Approaches to Characterize Arqa River Basin: A Typical Coastal Lebanese River

Water resources in Lebanon are one of the major threatened natural resources, since they spread on different geographic locations creating a network of permanent and temporary watercourses that govern the socio-economy and livelihood. However, lately, these watercourses, and certainly the rivers and streams, are witnessing unfavorable impacts that make them with less benefit and use. In addition, most of the Lebanese river basins have not been characterized due to the newly physical challenges of climate change and the human interference. Hence, characterization of the Lebanese river basins must be obtained in order to monitor the changing of physical and anthropogenic parameters. This can help for better conservation and adaptation approaches, notably for climate change. Arqa River, a coastal Lebanese river in North Lebanon is a typical example. In this study, Arqa River basin and the occupied streams among it have been studied using new advanced geomatic techniques. These techniques are based on the treatment of digital geo-spatial data in systematic approaches. ArcGIS is the software which is used to elaborate and manipulate (data interrelation, measures, overlapping, ordering, etc.) the geo-spatial data. Thus, the geometric and morphometric analysis were obtained for the river catchment and the existing tributaries. This will be a primary tool for further applications including water resources management in the river system. This can be utilized in the execution of dams, mountain lakes, man-made channels and in mapping flood-prone areas. In addition, the obtained characterization of this basin will be helpful in mapping erosion processes and estimation of the infiltration capacity, plus monitoring surface water flow. It is a typical approach of analysis that can be applied for the rest of Lebanese river systems in order to attain a better water resources management. This study shows that the use of geomatic techniques is a very helpful tool in the study of basins morphometry, and it can give valuable measures which cannot be applicable by conventional tools of analysis. In addition, it serves in reducing time of analysis with least cost, as well as it can cover rugged and remote areas.